In usual threat modelingthe information exchange among the threats is often ignored.To solve the problema target instruction probability model was established.On which basisa threat netting model based on detection probability was built up.Common path cost function was improved by using the threat netting model.The Differential Evolution Algorithm (DEA) was introducedand analysis was made to the effect of threat netting on threat intensity and threat cost of waypoint by using the method.Simulation was made to the effect of the threat netting model on path planningwhich shows the necessity and feasibility of threat netting model.